Fe biofortification of potato is a promising strategy to prevent Fe deficiency worldwide either through traditional breeding or biotechnological approaches. These approaches require the identification of candidate genes to uptake, transport and store Fe in potato tubers. We employed multiple approaches including SNP genotyping, QTL analysis, identifying genes orthologous to Arabidopsis ferrome, yeast complementation assay and genetic transformation to avoid the limitation from a single approach. We revealed several candidate genes potentially associated with potato plant Fe acquisition, PGSC0003DMG400024976 (metal transporter), PGSC0003DMG400013297 (oligopeptide transporter), PGSC0003DMG400021155 (IRT1) and IRTunannotated (an ortholog to the IRT gene that is not annotated in the potato genome). The microorganisms in the rhizosphere react intensely with the various metabolites released by plant roots in a variety of ways such as positive, negative, and neutral. These interactions can influence the uptake and transport of micronutrients in the plant roots. Therefore, the contribution of soil microorganisms in the rhizosphere to improve Fe supply of plants may play a key role in Fe biofortification, especially under real world field-based soil scenarios. We thus investigated rhizosphere microbial community diversity in Andean potato landraces to understand the role of plant-microbial interaction in potato Fe nutrient cycling. From the analysis of the high-throughput Illumina sequences of 16S and ITS region of ribosomal RNA gene, we found that both potato landraces with low and high Fe content in tubers and a landrace on which low or high Fe content fertilizer was applied to the leaf surface had large impacts on the rhizosphere fungal community composition. Indicator species analysis (ISA) indicated that Operational Taxonomic Units (OTUs) contributing most to these impacts were closely related to Eurotiomycetes and Leotiomycetes in the phylum Ascomycota, Glomeromycetes in the phylum Glomeromycota and Microbotryomycetes in the phylum Basidiomycota. Lots of species from these groups have been shown to regulate plant mineral nutrient cycling. Our research revealed potential candidate genes and fungal taxa involved in the potato plant Fe nutrient dynamics, which provides new insights into crop management and breeding strategies for sustainable Fe fortification in agricultural production. / Ph. D.

The organization of metabolism is an essential feature of cellular biochemistry. Metabolism does not occur as a linear assembly of freely diffusing enzymes, but as a complex web in which multiple interactions are possible. Because of the crowded environment of the cell, there must be structured and ordered mechanisms that control metabolic pathways. The following work will examine two metabolic pathways, one that is ubiquitous among living organisms and another that is entirely unique to plants, and examine the organization of each in an attempt to further define mechanisms that are fundamental features of metabolic control. One study offers some of the first characterizations of genes involved in [Fe-S] cluster assembly in Arabidopsis. The other explores the mechanisms that control localization of an enzyme that is part of the well-characterized flavonoid biosynthetic pathway. These two distinct pathways serve as unique models for genetic and biochemical studies that contribute to our overall understanding of plant metabolism. / Ph. D.

Casamance is a region in southern Senegal that traditionally produces rainfed rice, but Senegal produces only 1/3 of its rice consumption. Lowland areas, where rice is primarily produced, have acid sulfate soils with low pH and potential aluminum and iron toxicity. The goal of this work was to determine if soil amendments can alleviate soil acidity, counteract the negative biogeochemical effects that occur in flooded conditions, and increase rice yield. A two-year experiment was conducted to test the following soil treatments – agricultural lime, pulverized oyster shell, biochar, and control (no amendment) – in flat and raised beds. Plots amended with lime and shell materials had increased soil pH, base saturation, Ca, and cation exchange capacity. Meanwhile, biochar elevated particulate organic matter and C:N ratios. Exchangeable Fe and Al were negatively correlated with soil pH, while Geobacteraceae populations (Fe reducing bacteria) increased with pH. A greater proportion of the total Fe was strongly bound in fractions that were less bioavailable in plots amended with shell or lime, and overall rice yields were significantly higher following amendment with shell or lime. During the second growing year these effects diminished, suggesting that liming effects did not persist as expected. These results demonstrate the benefits of soil amendments that raise soil pH and suggest that this effect operates by influencing overall soil nutrient availability to rice plants, but further research is needed regarding the timing and sustainability of the beneficial liming effect. / Master of Science

Crack propagation studies in nanocrystalline alpha-iron samples with grain sizes ranging from 6 to 12 nm are reported at temperatures ranging from 100K to 600K using atomistic simulations. For all grain sizes, a combination of intragranular and intergranular fracture is observed. Mechanisms such as grain boundary accommodation, grain boundary triple junction, grain nucleation and grain rotation are observed to dictate the plastic deformation energy release. Intergranular fracture is shown to proceed by the coalescence of nanovoids formed at the grain boundaries ahead of the crack. The simulations also show that at an atomistic scale the fracture resistance and plastic deformation energy release mechanisms increase with increasing temperature. Finally a softening of the material occurs with decreasing grain size. The elastic properties are found to decrease and the fracture resistance to increase with decreasing grain size. / Master of Science

En el presente trabajo de investigación se realiza un análisis de la aplicación e interpretación por parte del Instituto Nacional de Defensa de la Competencia y de la Protección de la Propiedad Intelectual respecto a la categoría jurídica de la cláusula abusiva en relaciones jurídicas de consumo, y el posible riesgo de vulneración a la libertad de empresa que puede conllevar su utilización bajo determinadas circunstancias. En base a ello, partiendo de la definición de los conceptos de cláusula abusiva y libertad de empresa, y de una aproximación a sus principales características en el marco de un modelo de economía social de mercado, se cuestiona la necesidad de una interpretación por parte del Indecopi de realizar un análisis proporcional y adecuado de la realidad del mercado particular que atiende para evaluar la procedencia de la figura de la cláusula abusiva. Para este propósito, se lleva a cabo un análisis de las resoluciones Nº 0219-2018/SPCINDECOPI y Nº 0243-2018/SPC-INDECOPI, en cuyos pronunciamientos el Tribunal del Indecopi declaró como una cláusula abusiva de ineficacia absoluta la prohibición de Cineplex S.A. y Cinemark del Perú S.R.L. de ingresar a sus salas de cine con alimentos y/o bebidas adquiridas en establecimientos comerciales externos, vulnerando su libertad de empresa en su manifestación de libertad de organización. / In the present research work, an analysis of the application and interpretation is carried out by the Instituto Nacional de Defensa de la Competencia y de la Protección de la Propiedad Intelectual regarding the legal category of the abusive clause in consumer legal relations, and the possible risk of infringement of business freedom that its use may entail under certain circumstances. Based on this, based on the definition of the concepts of unfair terms and free enterprise, and an approximation to its main characteristics within the framework of a social market economy model, the need for an interpretation by the Indecopi to carry out a proportional and adequate analysis of the reality of the particular market that it attends to evaluate the origin of the figure of the abusive clause. For this purpose, an analysis of resolutions Nº 0219-2018/SPC-INDECOPI and Nº 0243- 2018/SPC-INDECOPI is carried out, in whose pronouncements the Indecopi Court declared the of Cineplex and Cinemark del Perú S.R.L. as an abusive clause of absolute ineffectiveness the prohibition of entering their movie theaters with food and/or drinks purchased in external commercial establishments, violating their freedom of enterprise in their manifestation of freedom of organization. / Trabajo académico

Giant magnetostrictive RFe2 type (R represents rare earths) intermetallics form an important class of magnetic materials keeping in view of their potential applications as sensors and/ or actuators. In this thesis, one such mixed rare earth compound (Tb,Dy)Fe2 has been chosen for investigations. Being a technologically important material system, several investigations concerning physical and magnetic properties of the material and effect of processing parameters on magnetic properties have been reported in the available literature. However, existing literature does not provide a clear insight into some important aspects such as phase equilibria, evolution of texture and microstructure of directionally solidified Tb-Dy-Fe alloys. Therefore, the present work was undertaken to bring out tangible process-structure-property correlations with an emphasis to clarify the grey areas in the available literature. The investigation on the nature of ternary phase equilibria of Tb-Dy-Fe was taken up with an aim to understand the effect of Tb/Dy ratio on phase equilibria and magnetic properties of TbxDy1-xFe1.95 (x=0-1) alloys. Microstructural and micro-chemical analysis along with study of lattice parameter has been used to predict the nature of phase equilibria and the deviation from the assumed pseudo-binary behaviour. Further, from the microstructural investigations and study of lattice parameter and Curie temperature, a schematic sketch of a section of the ternary diagram, where (Tb,Dy) / Fe =1.95, was formulated and presented. Directional solidification technique is the most widely adopted method for processing the (Tb,Dy)Fe2, to impart grain orientation for practical applications. Therefore, it was aimed in the present study to understand the evolution of texture and microstructure in directionally solidified Tb0.3Dy0.7Fe1.95 alloy by modified Bridgman and zone melting techniques. The alloy was directionally solidified by modified Bridgman technique with a series of growth rates 5 - 100 cm/h, at a constant temperature gradient of 150oC/ cm. Microstructural investigation revealed formation of island banding at lower growth rate and peritectic coupled growth at higher growth rates. The texture study indicated a transition of growth texture from <113> to <110> and finally to <112> with increase of growth rate. A mechanism based on atomic attachment kinetics is proposed to explain the orientation selection with growth rate. The texture and microstructure have been correlated with magnetostriction and static strain co-efficient (dλ/dH) of the Bridgman solidified alloys. The solidification morphology observed in Bridgman solidified samples was found to be mostly plane front. Therefore, in order to understand the microstructure and texture evolution in cellular/ dendritic regime, directional solidification of Tb0.3Dy0.7Fe1.95 was attempted by zone melting technique with a lesser temperature gradient of 100oC/cm. A detailed texture study indicated a transition in preferred growth direction from <110> to <112> with increase of growth rate. In this case of cellular/ dendritic growth regime, a mechanism based on atomic attachment kinetics has been proposed and the preferred morphologies of the solid-liquid interface for <110> and <112> growth have been modelled. The modelled interfaces have been correlated to the shape of cell/ dendrite cross-section observed for the growth rates adopted in this study. Apart from the investigation carried out on the (Tb,Dy)Fe2 alloys, attempts have been made to understand the role of microstructure, especially the ordered phases on the magnetostriction of an emerging magnetostrictive material Fe-Ga. A series of alloy compositions of Fe-x at % Ga (x=17, 20, 23 and 25) were prepared and subjected to different thermal treatments and characterized for microstructural features and magnetostriction. Microstructure investigation of slow cooled, quenched and quenched + aged alloys reveals formation of ordered DO3 phase from disordered A2 phase by first order transformation in 17 and 20 at% Ga alloys, whereas for 23 and 25 at% alloys, the transformation takes place by continuous ordering. It could be observed that large magnetostriction arises owing to the presence of disordered A2 phase or ordered DO3 phase alone. The magnetostriction however decreases substantially when these two phases are co-existing.

- An Plasmaschweißbrennern treten starke thermomechanische Beanspruchungen aufgrund der ablaufenden thermophysikalischen Teilprozesse auf. Diese können durch funktionsgerechte werkstoffliche, konstruktive und fertigungstechnische Brennergestaltung bewerkstelligt und die Thermobilanz und Lebensdauer der Brenner verbessert werden. - Anhand des entwickelten strömungs-thermomechanischen/magneto-hydro-dynamischen Simulationsmodells wurden werkstofflich-konstruktive Lösungsansätze für Entwicklung von physikalischen Prozesswirkprinzipien der betrachteten Plasma-Schweißprozessvarianten erarbeitet. - Differente Einflussgrößen des Plasmaschweißprozesses wurden erfasst, analysiert und ihre Wirkung auf Prozessverhalten und Brennerkonstruktion ermittelt. - Die damit gewonnenen Erkenntnisse wurden für werkstoffliche, technisch-konstruktive Brennerentwicklung bzgl. der Ausführungsgeometrien, Prozessgaszuführung und Brennerkühlung genutzt.

Les transitions de spin provoquent des changements de propriétés physiques des complexes de métaux du bloc d les subissant, notamment de leur structure et propriétés spectroscopiques. Ce mémoire porte sur la spectroscopie Raman de composés du fer(II) et du fer(III), pour lesquels on induit une transition de spin par variation de la température ou de la pression. Trois complexes de fer(II) de type FeN4(NCS)2 avec des comportements de transition de spin différents ont été étudiés : Fe(Phen)2(NCS)2 (Phen : 1,10-Phénanthroline), Fe(Btz)2(NCS)2 (Btz : 2,2’-bi-4,5-dihydrothiazine) et Fe(pyridine)4(NCS)2. Un décalage de l’ordre de 50 cm-1 est observable pour la fréquence d’étirement C-N du ligand thiocyanate des complexes FeN4(NCS)2, lors de la transition de spin induite par variation de la température ou de la pression. Il est possible d’utiliser cette variation de fréquence afin de tracer un profil de transition. Quatre complexes isomères de type FeL222(CN)2 (L222 : 2,13- diméthyl-6,9-dioxa-3,12,18-triazabicyclo[12.3.1]-octadéca-1(18),2,12,14,16-pentaène) ont également été étudiés. Un taux de décalage de l’ordre d’environ 0,03 cm-1/K est observé pour plusieurs bandes du complexe FeL222(CN)2. La bande à 1415 cm-1 disparaît à plus haute température au profit d’une bande à 1400 cm-1. Pour le complexe de chiralité R,R’, les bandes à 1008 cm-1 et 1140 cm-1 se déplacent vers des fréquences plus élevées à partir de 223 K. Les transitions de spin sont observées dans certains complexes de fer(III). Dans cette famille de composés, le complexe Fe(EtDTC)3 (EtDTC : N,N-diéthyldithiocarbamate) a été étudié . Aucun changement n’a été observé dans l’intensité des bandes d’étirement fer-soufre sur les spectres à température variable. Cependant, la bande Fe-S associée à la forme bas-spin à 530 cm-1 augmente en intensité au profit de la bande associée à la forme haut-spin à 350 cm-1 lors des mesures à haute pression, passant d’un rapport d’amplitude de 50% à pression ambiante à 80% à 21 kbar. Un dédoublement de la bande d’étirement C-N du ligand dithiocarbamate à 1495 cm-1 est également observé à des pressions supérieures à 5 kbar. Une comparaison des changements des fréquences de vibration de tous les complexes est effectuée. / AbstractSpin crossover processes lead to significant changes of molecular structures and spectroscopic properties measured for complexes of d-block transition metals. This thesis focuses on vibrational Raman spectroscopy of iron(II) and iron(III) compounds with spin transitions induced through temperature and pressure variations. Three iron(II) complexes of type FeN4(NCS)2 with different spin transition patterns have been studied: Fe(Phen)2(NCS)2 (Phen : 1,10-Phenanthroline), Fe(Btz)2(NCS)2 (Btz : 2,2’-bi-4,5- dihydrothiazine) and Fe(pyridine)4(NCS)2. A 50 cm-1 shift has been found for the C-N stretching frequency of the thiocyanate ligand in these compounds as a consequence of the spin transition induced by temperature or pressure. These frequency variations have been used to trace different transition profiles. Four different isomers of FeL222(CN)2 (L222 : [2,13-dimethyl-6,9-dioxa-3,12,18-triazabicyclo[12.3.1]-octadeca-1(18),2,12,14,16- pentaene]) type complexes have also been studied. A variation with temperature of approximately 0,03 cm-1/K has been observed for a few bands for the FeL222(CN)2 complex. A band at 1415 cm-1 decreases in intensity in favour of a band at 1400 cm-1 as temperature rises. The bands at 1008 cm-1 and 1140 cm-1 for the complex of R,R’ configuration shift to higher frequencies around 223 K. Spin transitions have also been investigated in some iron(III) complexes. In this family of compounds, the Fe(EtDTC)3 (EtDTC : N,N-diéthyldithiocarbamate) complex has been studied. No change has been observed in the intensity of the iron-sulphur stretching bands in spectra measured at variable temperature. However, at high pressure the low-spin Fe-S band at 530 cm-1 gains intensity compared to the high spin band at 350 cm-1. A splitting of the C-N stretching band of the dithiocarbamate ligand at 1495 cm-1 is observed at pressures above 5 kbar. A comparison of all changes in vibrational spectra is presented.

L’objectif de ce travail est d’évaluer l’effet de la nature du support et l’effet de promotion sur les propriétés catalytiques des catalyseurs d’HDS à base de Mo. Pour obtenir les systèmes catalytiques adéquats, nous avons appliqué la préparation par « voie acac », qui consiste à faire réagir le promoteur sous forme de complexe acétylacétonate (de Co, Ni ou Fe) sur le sulfure de molybdène supporté (sur γ-Al2O3, SiO2, TiO2 ou ZrO2). Les différents solides obtenus ont été caractérisés par MET, IR(CO) et SPX notamment pour tenter de quantifier les phases actives, puis ils ont été testés dans les réactions d’HDS du thiophène et du 4,6-DMDBT. L’activité catalytique a pu être corrélée aux résultats de caractérisation par une nouvelle approche qui consiste à calculer l’activité apparente par site NiMoS ou CoMoS. Cette approche montre que la qualité des sites actifs CoMoS et NiMoS est la meilleure sur SiO2 et comparable sur les supports γ-Al2O3, TiO2 et ZrO2. Par la même méthode nous avons préparé de nouveaux catalyseurs de type CoNiMoS supportés, en ajoutant les promoteurs Co et Ni soit simultanément soit successivement au MoS2. Cette étude permet un fort apport expérimental aux études théoriques qui avancent l’hypothèse de différentes affinités du Co et du Ni pour les deux type de bords S-edge et Mo-edge sur γ-Al2O3 et TiO2. / The main objective of this work was to evaluate the support and the promoting effect on the catalytic properties of HDS catalysts. In order to obtain appropriate catalytic systems, we applied the “acac method” which consists to add the promoter as an acetylacetonate complex (of Co, Ni or Fe) onto the supported molybdenum sulfide (on γ-Al2O3, SiO2, TiO2 and ZrO2). The various solids obtained were characterized by TEM, IR(CO) and XPS in particular to quantify the active phases, and then they have been tested in the HDS reactions of thiophene and 4,6-DMDBT. The catalytic activity has been correlated to the characterization datas by a new approach which consists in calculating the apparent catalytic activity by NiMoS or CoMoS site. This approach showed that the quality of the active sites is the best on SiO2 and comparable on γ-Al2O3, TiO2 and ZrO2. Moreover, this “acac method” allowed us to study supported CoNiMoS catalysts synthesized by adding Co and Ni either simultaneously or successively to MoS2. This study represents an important experimental contribution which allow to discuss the hypothesis developped in theoretical studies about the different affinities of Co and Ni for the S-edge and Mo-edge on γ-Al2O3 and TiO2.

Les alliages à base de chrome sont couramment utilisés pour des applications à haute température. Leurs capacités à former une couche d’oxyde thermique protectrice permet de réduire les cinétiques d’oxydation de ces matériaux. En particulier, les alliages Ni-Cr et Fe-Cr forment une couche continue de α-Cr2O3 en surface. La durabilité du système métal/céramique résultant dépend de l’intégrité mécanique de cette couche, et donc des mécanismes d’endommagement susceptibles de se produire lors de l’oxydation ou du refroidissement. L’endommagement est étroitement corrélé au niveau de contraintes résiduelles dans l’oxyde mais aussi à sa microstructure. Dans ces travaux, des alliages Ni-30Cr et Fe-47Cr sont oxydés à l’air à 800, 900 et 1000°C et une approche multi-échelle est proposée pour analyser rigoureusement les contraintes résiduelles aussi bien à des échelles macroscopiques dans le film d’oxyde adhérent qu’à des échelles locales au travers de régions délaminées.A l’échelle macroscopique, les niveaux de contraintes résiduelles sont déterminés grâce à la diffraction des Rayons X conventionnelle et à la spectroscopie Raman. Les taux de délamination des couches d’oxyde et les phénomènes de fluage diffusionnel sont quantifiés en fonction de paramètres métallurgiques conduisant à différents états microstructuraux du système. L’influence de la compétition entre ces deux modes de relaxation de contrainte sur l’endommagement est discutée. A l’échelle microscopique, des cartographies de contraintes résiduelles au travers de différents types de délaminations sont réalisées grâce à la microspectroscopie Raman et à la microdiffraction Synchrotron. En raison de sa résolution latérale, la microspectroscopie Raman est particulièrement appropriée pour analyser les délaminations formées localement. Des observations par microscopie à force atomique ont également été menées afin de décrire la géométrie (dimensions, hauteur) des différents types d’objets délaminés. Ces informations morphologiques complémentaires couplées aux niveaux de contraintes associés permettent une confrontation aux lois de la mécanique du cloquage, et l’extraction de l’adhérence interfaciale. A partir de ces analyses, des schémas et cartes de l’endommagement des couches de chromine sont proposés. / Chromia-former alloy are mainly used for high temperature applications. Their ability to form a protective thermal oxide scale allows reducing oxidation kinetics of the materials. In particular, Ni-Cr and Fe-Cr alloy forms a α-Cr2O3 scale at the surface. Durability of the metal/ceramic system depends on the mechanical integrity of this scale, and also of the scale damage which could appear during oxidation or cooling. These scale damages are closely correlated to the residual stress magnitude in the oxide and to the microstructure. In this work, Ni-30Cr and Fe-47Cr alloys oxidized in air at 800, 900 and 1000°C and a multi-scale approach is proposed to a analyse with accuracy residual stress magnitude both at macroscopic scale in the adherent oxide and at local scale through delaminated area.At macroscopic scale, residual stress magnitudes are determined thanks to conventional X-Ray diffraction and Raman spectroscopy. Delamination rate in the oxide scale and diffusional creep phenomena are quantified in function of metallurgical parameters leadings to different microstructural state of the system. The influence of competition between these two stress release modes on scale damage is discussed. At microscopic scale, residual stress map through different types of delamination are performed thanks to Raman microspectroscopy and Synchrotron microdiffraction. Raman microspectroscopy is particularly appropriated to analyze delamination locally formed, due to its lateral resolution. Observations by atomic force microscopy have been performed to describe the different delamination type (dimension, height). These morphological information and associated residual stresses allows confrontation to buckling mechanic and calculation of the interface toughness. Diagrams and maps concerning the scale damages have been done thanks to these analyses.